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10 pages, 2559 KiB

Open AccessCommunication

Study on Gas Sorption and Iodine Uptake of a Metal-Organic Framework Based on Curcumin

by Hongmin Su, Yang Zhou, Tao Huang and Fuxing Sun

Molecules 2023, 28(13), 5237; https://doi.org/10.3390/molecules28135237 - 06 Jul 2023

Viewed by 1253

Abstract

Medi-MOF-1 is a highly porous Metal-Organic framework (MOF) constructed from Zn(II) and curcumin. The obtained crystal was characterized using powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). A micrometer-sized crystal with similar morphology was successfully obtained using the solvothermal method. Thanks to [...] Read more.

Medi-MOF-1 is a highly porous Metal-Organic framework (MOF) constructed from Zn(II) and curcumin. The obtained crystal was characterized using powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). A micrometer-sized crystal with similar morphology was successfully obtained using the solvothermal method. Thanks to its high surface area, good stability, and abound pores, the as-synthesized medi-MOF-1 could be used as a functional porous material to adsorb different gases (H₂, CO₂, CH₄, and N₂) and iodine (I₂). The activated sample exhibited a high I₂ adsorption ability of 1.936 g g^–1 at room temperature via vapor diffusion. Meanwhile, the adsorbed I₂ could be released slowly in ethanol, confirming the potential application for I₂ adsorption. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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14 pages, 5693 KiB

Open AccessArticle

Fabrication of Hierarchically Porous CuBTC@PA-PEI Composite for High-Efficiency Elimination of Cyanogen Chloride

by Xuanlin Yang, Liang Lan, Chao Zheng, Kai Kang, Hua Song, Shuyuan Zhou and Shupei Bai

Molecules 2023, 28(6), 2440; https://doi.org/10.3390/molecules28062440 - 07 Mar 2023

Cited by 1 | Viewed by 1257

Abstract

Cyanogen chloride (CNCl) is highly toxic and volatile, and it is difficult to effectively remove via porous substances such as activated carbon due to the weak interaction between CNCl and the adsorbent surface. Developing a highly effective elimination material against CNCl is of [...] Read more.

Cyanogen chloride (CNCl) is highly toxic and volatile, and it is difficult to effectively remove via porous substances such as activated carbon due to the weak interaction between CNCl and the adsorbent surface. Developing a highly effective elimination material against CNCl is of great importance in military chemical protection. In this work, a new metal-organic framework (MOF) CuBTC@PA-PEI (polyacrylate-polyethyleneimine) composite was prepared and exhibited excellent CNCl elimination performance in the breakthrough tests. PEI was used for the functionalization of PA with amino groups, which is beneficial to anchor with metal ions of MOF. Afterward, the growth of MOF occurred on the surface and in the pores of the matrix by molecular self-assembly via our newly proposed stepwise impregnation layer-by-layer growth method. Breakthrough tests were performed to evaluate the elimination performance of the composites against CNCl. Compared with the pristine CuBTC powder, the CuBTC@PA-PEI composite exhibited better adsorption capacity and a longer breakthrough time. By compounding with the PA matrix, a hierarchically porous structure of CuBTC@PA-PEI composite was constructed, which provides a solution to the mass transfer problem of pure microporous MOF materials. It also solves the problems of MOF molding and lays a foundation for the practical application of MOF. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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11 pages, 4294 KiB

Open AccessArticle

Arrangement of Indocyanine Green in a 1.5-Nanometer Channel to Achieve High-Efficiency Imaging of the Intestinal Lymphatic System

by Xiangyi Kong, Nan Gao, Jianshi Du and Qing Zhao

Molecules 2022, 27(24), 8704; https://doi.org/10.3390/molecules27248704 - 08 Dec 2022

Viewed by 973

Abstract

The complications of inflammatory bowel diseases (IBDs) seriously endanger people’s health, such as bleeding, polyp hyperplasia, and even cancer. Although the precise pathophysiology of IBD is unknown, alterations in the intestinal lymphatic network, such as lymphangiogenesis and lymphatic vessel dysfunction, are well-established features. [...] Read more.

The complications of inflammatory bowel diseases (IBDs) seriously endanger people’s health, such as bleeding, polyp hyperplasia, and even cancer. Although the precise pathophysiology of IBD is unknown, alterations in the intestinal lymphatic network, such as lymphangiogenesis and lymphatic vessel dysfunction, are well-established features. Therefore, the development of a reliable technology is urgently required, with a stereoscopic, deep, and high-resolution technology for IBD lymphatic targeting imaging in clinical practice. However, indocyanine green, the only clinically approved imaging agent by the Food and Drug Administration, can easily cause self-aggregation or be interfered with by microenvironments, causing fluorescence quenching, which seriously affects the imaging and detective capabilities. Herein, indocyanine green molecules are arranged in a 1.5-nanometer one-dimensional channel (TpPa-1@ICG). Based on this specified structure, the fluorescence enhancement effect is observed in the TpPa-1@ICG resultant, and the fluorescence intensity is enhanced by 27%. In addition, the ICG-incorporated porous solid reveals outstanding solvent (dichloromethane, tetrahydrofuran, etc.) and thermal (>300 °C) stability. After modifying the target molecules, TpPa-1@ICG showed excellent imaging ability for intestinal lymphatic vessels, providing a new imaging tool for IBDs research. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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10 pages, 2552 KiB

Open AccessArticle

Facile Synthesis of Highly Emissive All-Inorganic Manganese Bromide Compounds with Perovskite-Related Structures for White LEDs

by Ping Gao, Suwen Cheng, Jiaxin Liu, Junjie Li, Yanyan Guo, Zhengtao Deng, Tianshi Qin and Aifei Wang

Molecules 2022, 27(23), 8259; https://doi.org/10.3390/molecules27238259 - 26 Nov 2022

Cited by 4 | Viewed by 1987

Abstract

Lead-free all-inorganic halide materials with different Mn²⁺-based crystal structures (Cs₃MnBr₅ and CsMnBr₃) were obtained using a convenient synthetic method. Cs₃MnBr₅ had a bright green emission (522 nm), with a unique single-exponential lifetime (τ [...] Read more.

Lead-free all-inorganic halide materials with different Mn²⁺-based crystal structures (Cs₃MnBr₅ and CsMnBr₃) were obtained using a convenient synthetic method. Cs₃MnBr₅ had a bright green emission (522 nm), with a unique single-exponential lifetime (τ_avg = 236 µs) and a high photoluminescence quantum yield (82 ± 5%). A red emission was observed in the case of the CsMnBr₃ structure with a two-exponential fluorescence decay curve, and the lifetime was 1.418 µs (93%) and 18.328 µs (7%), respectively. By a judicious tuning of the synthetic conditions, a mixed phase of Cs₃MnBr₅/CsMnBr₃ was also produced that emitted white light, covering almost the entire visible spectrum. White-light-emitting diodes (WLEDs) with color coordinates (0.4269, 0.4955), a color temperature of (3773 K), and a color rendering index (68) were then fabricated using the as-prepared powder of mixed phases of Cs₃MnBr₅/CsMnBr₃ with a commercial UV LED chip (365 nm). Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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9 pages, 16153 KiB

Open AccessArticle

An Azo-Group-Functionalized Porous Aromatic Framework for Achieving Highly Efficient Capture of Iodine

by Zhuojun Yan, Yimin Qiao, Jiale Wang, Jialin Xie, Bo Cui, Yu Fu, Jiawei Lu, Yajie Yang, Naishun Bu, Ye Yuan and Lixin Xia

Molecules 2022, 27(19), 6297; https://doi.org/10.3390/molecules27196297 - 23 Sep 2022

Cited by 8 | Viewed by 1768

Abstract

The strong radioactivity of iodine compounds derived from nuclear power plant wastes has motivated the development of highly efficient adsorbents. Porous aromatic frameworks (PAFs) have attracted much attention due to their low density and diverse structure. In this work, an azo group containing [...] Read more.

The strong radioactivity of iodine compounds derived from nuclear power plant wastes has motivated the development of highly efficient adsorbents. Porous aromatic frameworks (PAFs) have attracted much attention due to their low density and diverse structure. In this work, an azo group containing PAF solid, denoted as LNU-58, was prepared through Suzuki polymerization of tris-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)-amine and 3,5-dibromoazobenzene building monomers. Based on the specific polarity properities of the azo groups, the electron-rich aromatic fragments in the hierarchical architecture efficiently capture iodine molecules with an adsorption capacity of 3533.11 mg g⁻¹ (353 wt%) for gaseous iodine and 903.6 mg g⁻¹ (90 wt%) for dissolved iodine. The iodine uptake per specific surface area up to 8.55 wt% m⁻² g⁻¹ achieves the highest level among all porous adsorbents. This work illustrates the successful preparation of a new type of porous adsorbent that is expected to be applied in the field of practical iodine adsorption. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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9 pages, 2877 KiB

Open AccessArticle

Integrating a Luminescent Porous Aromatic Framework into Indicator Papers for Facile, Rapid, and Selective Detection of Nitro Compounds

by Bo Cui, Changyuan Gao, Jiating Fan, Jinni Liu, Bin Feng, Xianghui Ruan, Yajie Yang, Ye Yuan, Kuo Chu, Zhuojun Yan and Lixin Xia

Molecules 2022, 27(19), 6252; https://doi.org/10.3390/molecules27196252 - 22 Sep 2022

Cited by 3 | Viewed by 1414

Abstract

Porous aromatic framework materials with high stability, sensitivity, and selectivity have great potential to provide new sensors for optoelectronic/fluorescent probe devices. In this work, a luminescent porous aromatic framework material (LNU-23) was synthesized via the palladium-catalyzed Suzuki cross-coupling reaction of tetrabromopyrene and 1,2-bisphenyldiborate [...] Read more.

Porous aromatic framework materials with high stability, sensitivity, and selectivity have great potential to provide new sensors for optoelectronic/fluorescent probe devices. In this work, a luminescent porous aromatic framework material (LNU-23) was synthesized via the palladium-catalyzed Suzuki cross-coupling reaction of tetrabromopyrene and 1,2-bisphenyldiborate pinacol ester. The resulting PAF solid exhibited strong fluorescence emission with a quantum yield of 18.31%, showing excellent light and heat stability. Because the lowest unoccupied molecular orbital (LUMO) of LNU-23 was higher than that of the nitro compounds, there was an energy transfer from the excited LNU-23 to the analyte, leading to the selective fluorescence quenching with a limit of detection (LOD) ≈ 1.47 × 10⁻⁵ M. After integrating the luminescent PAF powder on the paper by a simple dipping method, the indicator papers revealed a fast fluorescence response to gaseous nitrobenzene within 10 s, which shows great potential in outdoor fluorescence detection of nitro compounds. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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8 pages, 1854 KiB

Open AccessArticle

Introducing Polar Groups in Porous Aromatic Framework for Achieving High Capacity of Organic Molecules and Enhanced Self-Cleaning Applications

by Zhuojun Yan, Yimin Qiao, Qiqi Sun, Bo Cui, Bin Feng, Naishun Bu, Kuo Chu, Xianghui Ruan, Ye Yuan, Yajie Yang and Lixin Xia

Molecules 2022, 27(18), 6113; https://doi.org/10.3390/molecules27186113 - 19 Sep 2022

Cited by 1 | Viewed by 1477

Abstract

Due to the frequent oil/organic solvent leakage, efficient oil/water separation has attracted extensive concern. However, conventional porous materials possess nonpolar building units, which reveal relatively weak affinity for polar organic molecules. Here, two different polarities of superhydrophobic porous aromatic frameworks (PAFs) were synthesized [...] Read more.

Due to the frequent oil/organic solvent leakage, efficient oil/water separation has attracted extensive concern. However, conventional porous materials possess nonpolar building units, which reveal relatively weak affinity for polar organic molecules. Here, two different polarities of superhydrophobic porous aromatic frameworks (PAFs) were synthesized with respective orthoposition and paraposition C=O groups in the PAF linkers. The conjugated structure formed by a large number of alkynyl and benzene ring structures enabled porous and superhydrophobic quality of PAFs. After the successful preparation of the PAF solids, PAF powders were coated on polyester fabrics by a simple dip-coating method, which endowed the resulting polyester fabrics with superhydrophobicity, porosity, and excellent stability. Based on the unique structure, the oil/water separation efficiency of two superhydrophobic flexible fabrics was more than 90% for various organic solvents. Polar LNU-26 PAF showed better separation performance for the polar oils. This work takes the lead in adopting the polar groups as building units for the preparation of porous networks, which has great guiding significance for the construction of advanced oil/water separation materials. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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19 pages, 4947 KiB

Open AccessArticle

Preparation, Characterization, and In Vitro Release of Curcumin-Loaded IRMOF-10 Nanoparticles and Investigation of Their Pro-Apoptotic Effects on Human Hepatoma HepG2 Cells

by Dongge Yin, Xueling Hu, Mengru Cai, Kaixin Wang, Hulinyue Peng, Jie Bai, Yvchen Xv, Tingting Fu, Xiaoxv Dong, Jian Ni and Xingbin Yin

Molecules 2022, 27(12), 3940; https://doi.org/10.3390/molecules27123940 - 20 Jun 2022

Cited by 6 | Viewed by 2105

Abstract

Curcumin (CUR) has a bright future in the treatment of cancer as a natural active ingredient with great potential. However, curcumin has a low solubility, which limits its clinical application. In this study, IRMOF-10 was created by the direct addition of triethylamine, CUR [...] Read more.

Curcumin (CUR) has a bright future in the treatment of cancer as a natural active ingredient with great potential. However, curcumin has a low solubility, which limits its clinical application. In this study, IRMOF-10 was created by the direct addition of triethylamine, CUR was loaded into IRMOF-10 using the solvent adsorption method, and the two were characterized using a scanning electron microscope (SEM), X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG) methods, and Brunauer–Emmett–Teller (BET) analysis. We also used the MTT method, 4′,6-diamidino-2-phenylindole (DAPI) staining, the annexin V/PI method, cellular uptake, reactive oxygen species (ROS), and the mitochondrial membrane potential (MMP) to perform a safety analysis and anticancer activity study of IRMOF-10 and CUR@IRMOF-10 on HepG2 cells. Our results showed that CUR@IRMOF-10 had a CUR load of 63.96%, with an obvious slow-release phenomenon. The CUR levels released under different conditions at 60 h were 33.58% (pH 7.4) and 31.86% (pH 5.5). Cell experiments proved that IRMOF-10 was biologically safe and could promote curcumin entering the nucleus, causing a series of reactions, such as an increase in reactive oxygen species and a decrease in the mitochondrial membrane potential, thereby leading to cell apoptosis. In summary, IRMOF-10 is an excellent drug carrier and CUR@IRMOF-10 is an effective anti-liver cancer sustained-release preparation. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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9 pages, 20986 KiB

Open AccessFeature PaperArticle

A Facile and Highly Efficient Approach to Obtain a Fluorescent Chromogenic Porous Organic Polymer for Lymphatic Targeting Imaging

by Man Duan, Dongmei Han, Nan Gao, Wenbin Shen, Kun Chang, Xinyu Wang and Jianshi Du

Molecules 2022, 27(5), 1558; https://doi.org/10.3390/molecules27051558 - 25 Feb 2022

Cited by 2 | Viewed by 1554

Abstract

Porous organic polymers have an open architecture, excellent stability, and tunable structural components, revealing great application potential in the field of fluorescence imaging, but this part of the research is still in its infancy. In this study, we aimed to tailor the physical [...] Read more.

Porous organic polymers have an open architecture, excellent stability, and tunable structural components, revealing great application potential in the field of fluorescence imaging, but this part of the research is still in its infancy. In this study, we aimed to tailor the physical and chemical characteristics of indocyanine green using sulfonic acid groups and conjugated fragments, and prepared amino-grafted porous polymers. The resulting material had excellent solvent and thermal stability, and possessed a relatively large pore structure with a size of 3.4 nm. Based on the synergistic effect of electrostatic bonding and π–π interactions, the fluorescent chromogenic agent, indocyanine green, was tightly incorporated into the pore cavity of POP solids through a one-step immersion method. Accordingly, the fluorescent chromogenic POP demonstrated excellent imaging capabilities in biological experiments. This preparation of fluorescent chromogenic porous organic polymer illustrates a promising application of POP-based solids in both fluorescence imaging and biomedicine applications. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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11 pages, 2449 KiB

Open AccessArticle

Pyrene-Based Fluorescent Porous Organic Polymers for Recognition and Detection of Pesticides

by Zhuojun Yan, Jinni Liu, Congke Miao, Pinjie Su, Guiyue Zheng, Bo Cui, Tongfei Geng, Jiating Fan, Zhiyi Yu, Naishun Bu, Ye Yuan and Lixin Xia

Molecules 2022, 27(1), 126; https://doi.org/10.3390/molecules27010126 - 26 Dec 2021

Cited by 12 | Viewed by 3521

Abstract

Eating vegetables with pesticide residues over a long period of time causes serious adverse effects on the human body, such as acute poisoning, chronic poisoning, and endocrine system interference. To achieve the goal of a healthy society, it is an urgent issue to [...] Read more.

Eating vegetables with pesticide residues over a long period of time causes serious adverse effects on the human body, such as acute poisoning, chronic poisoning, and endocrine system interference. To achieve the goal of a healthy society, it is an urgent issue to find a simple and effective method to detect organic pesticides. In this work, two fluorescent porous organic polymers, LNU-45 and LNU-47 (abbreviation for Liaoning University), were prepared using π-conjugated dibromopyrene monomer and boronic acid compounds as building units through a Suzuki coupling reaction. Due to the large π-electron delocalization effect, the resulting polymers revealed enhanced fluorescence performance. Significantly, in sharp contrast with the planar π-conjugated polymer framework (LNU-47), the distorted conjugated structure (LNU-45) shows a higher specific surface area and provides a broad interface for analyte interaction, which is helpful to achieve rapid response and detection sensitivity. LNU-45 exhibits strong fluorescence emission at 469 nm after excitation at 365 nm in THF solution, providing strong evidence for its suitability as a luminescent chemosensor for organic pesticides. The fluorescence quenching coefficients of LNU-45 for trifluralin and dicloran were 5710 and 12,000 (LNU-47 sample by ca. 1.98 and 3.38 times), respectively. Therefore, LNU-45 serves as an effective “real-time” sensor for the detection of trifluralin and dicloran with high sensitivity and selectivity. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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14 pages, 3105 KiB

Open AccessArticle

Ionic Porous Aromatic Framework as a Self-Degraded Template for the Synthesis of a Magnetic γ-Fe₂O₃/WO₃·0.5H₂O Hybrid Nanostructure with Enhanced Photocatalytic Property

by Man Xu, Kai Wang and Xuan Cao

Molecules 2021, 26(22), 6857; https://doi.org/10.3390/molecules26226857 - 13 Nov 2021

Cited by 1 | Viewed by 1741

Abstract

An ionic porous aromatic framework is developed as a self-degraded template to synthesize the magnetic heterostructure of γ-Fe₂O₃/WO₃·0.5H₂O. The Fe₃O₄ polyhedron was obtained with the two-phase method first and then reacted with [...] Read more.

An ionic porous aromatic framework is developed as a self-degraded template to synthesize the magnetic heterostructure of γ-Fe₂O₃/WO₃·0.5H₂O. The Fe₃O₄ polyhedron was obtained with the two-phase method first and then reacted with sodium tungstate to form the γ-Fe₂O₃/WO₃·0.5H₂O hybrid nanostructure. Under the induction effect of the ionic porous network, the Fe₃O₄ phase transformed to the γ-Fe₂O₃ state and complexed with WO₃·0.5H₂O to form the n-n heterostructure with the n-type WO₃·0.5H₂O on the surface of n-type γ-Fe₂O₃. Based on a UV-Visible analysis, the magnetic photocatalyst was shown to have a suitable band gap for the catalytic degradation of organic pollutants. Under irradiation, the resulting γ-Fe₂O₃/WO₃·0.5H₂O sample exhibited a removal efficiency of 95% for RhB in 100 min. The charge transfer mechanism was also studied. After the degradation process, the dispersed powder can be easily separated from the suspension by applying an external magnetic field. The catalytic activity displayed no significant decrease after five recycles. The results present new insights for preparing a hybrid nanostructure photocatalyst and its potential application in harmful pollutant degradation. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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10 pages, 2376 KiB

Open AccessArticle

Construction of a Luminescent Cadmium-Based Metal–Organic Framework for Highly Selective Discrimination of Ferric Ions

by Li-Li Xu, Qiu-Feng Zhang, Dong Wang, Guang-Wei Wu and Hong Cai

Molecules 2021, 26(22), 6847; https://doi.org/10.3390/molecules26226847 - 13 Nov 2021

Cited by 7 | Viewed by 1763

Abstract

Fluorescent metal–organic frameworks (MOFs) are ideal materials for sensors because of their adjustable pore size and functional groups, which provide them with favorable metal ion selective recognition. In this paper, a new cadmium-based MOF was synthesized using Cd(NO₃)₂·4H₂ [...] Read more.

Fluorescent metal–organic frameworks (MOFs) are ideal materials for sensors because of their adjustable pore size and functional groups, which provide them with favorable metal ion selective recognition. In this paper, a new cadmium-based MOF was synthesized using Cd(NO₃)₂·4H₂O and 3,3′,5,5′-biphenyltetracarboxylic acid by solvothermal method. CdBPTC owned three types of channels with dimensions of approximately 8.4 × 8.3 Å, 6.0 × 5.2 Å, 9.7 × 8.4 Å along a, b, and c axis, respectively. This MOF has high selectivity to ferric ions and shows excellent anti-inference ability toward many other cations. The results indicate that the fluorescence quenching efficiency of CdBPTC is close to 100% when the concentration of Fe³⁺ reaches 1.0 × 10⁻³ mol·L⁻¹. Moreover, the luminescent intensity at 427 nm presents a linear relationship at a concentration range of 2.0 × 10⁻⁴~7.0 × 10⁻⁴ mol·L⁻¹, which can be quantitatively expressed by the linear Stern–Volmer equation I₀/I = 8489 [Fe³⁺] − 0.1400, which is comparable to the previously reported better-performing materials. Competitive energy absorption and ion exchange may be responsible for the variation in fluorescence intensity of CdBPTC in different Fe³⁺ concentrations. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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10 pages, 2961 KiB

Open AccessArticle

A Carbazole-Functionalized Porous Aromatic Framework for Enhancing Volatile Iodine Capture via Lewis Electron Pairing

by Zhuojun Yan, Bo Cui, Ting Zhao, Yifu Luo, Hongcui Zhang, Jialin Xie, Na Li, Naishun Bu, Ye Yuan and Lixin Xia

Molecules 2021, 26(17), 5263; https://doi.org/10.3390/molecules26175263 - 30 Aug 2021

Cited by 7 | Viewed by 2479

Abstract

Nitrogen-rich porous networks with additional polarity and basicity may serve as effective adsorbents for the Lewis electron pairing of iodine molecules. Herein a carbazole-functionalized porous aromatic framework (PAF) was synthesized through a Sonogashira–Hagihara cross-coupling polymerization of 1,3,5-triethynylbenzene and 2,7-dibromocarbazole building monomers. The resulting [...] Read more.

Nitrogen-rich porous networks with additional polarity and basicity may serve as effective adsorbents for the Lewis electron pairing of iodine molecules. Herein a carbazole-functionalized porous aromatic framework (PAF) was synthesized through a Sonogashira–Hagihara cross-coupling polymerization of 1,3,5-triethynylbenzene and 2,7-dibromocarbazole building monomers. The resulting solid with a high nitrogen content incorporated the Lewis electron pairing effect into a π-conjugated nano-cavity, leading to an ultrahigh binding capability for iodine molecules. The iodine uptake per specific surface area was ~8 mg m⁻² which achieved the highest level among all reported I₂ adsorbents, surpassing that of the pure biphenyl-based PAF sample by ca. 30 times. Our study illustrated a new possibility for introducing electron-rich building units into the design and synthesis of porous adsorbents for effective capture and removal of volatile iodine from nuclear waste and leakage. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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9 pages, 1838 KiB

Open AccessArticle

Rational Construction of a Responsive Azo-Functionalized Porous Organic Framework for CO₂ Sorption

by Rongrong Yuan, Hao Sun and Hongming He

Molecules 2021, 26(16), 4993; https://doi.org/10.3390/molecules26164993 - 18 Aug 2021

Cited by 2 | Viewed by 1760

Abstract

An azo-functionalized porous organic framework (denoted as JJU-1) was synthesized via FeCl₃-promoted oxidative coupling polymerization. By virtue of a porous skeleton and a light/heat responsive azo functional group, this task-specific JJU-1 displays a reversible stimuli-responsive adsorption property triggered by UV irradiation [...] Read more.

An azo-functionalized porous organic framework (denoted as JJU-1) was synthesized via FeCl₃-promoted oxidative coupling polymerization. By virtue of a porous skeleton and a light/heat responsive azo functional group, this task-specific JJU-1 displays a reversible stimuli-responsive adsorption property triggered by UV irradiation and heat treatment. The initial Brunauer–Emmet–Teller (BET) surface area of this porous material is 467 m² g^–1. The CO₂ sorption isotherms exhibit a slight decrease after UV irradiation because of the trans to cis conversion of the azo functional skeleton. It is worth mentioning that the responsive CO₂ adsorption performance can be recycled for three cycles via alternating external stimuli, confirming the excellently reversible switchability of trans-to-cis isomerization and controllable CO₂ adsorption. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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Review

Jump to: Research

30 pages, 6703 KiB

Open AccessReview

Molecular Design of Porous Organic Polymer-Derived Carbonaceous Electrocatalysts for Pinpointing Active Sites in Oxygen Reduction Reaction

by Xiaofeng Mou, Xiaoyu Xin, Yanli Dong, Bin Zhao, Runze Gao, Tianao Liu, Na Li, Huimin Liu and Zhichang Xiao

Molecules 2023, 28(10), 4160; https://doi.org/10.3390/molecules28104160 - 18 May 2023

Cited by 3 | Viewed by 1753

Abstract

The widespread application of fuel cells is hampered by the sluggish kinetics of the oxygen reduction reaction (ORR), which traditionally necessitates the use of high-cost platinum group metal catalysts. The indispensability of these metal catalysts stems from their ability to overcome kinetic barriers, [...] Read more.

The widespread application of fuel cells is hampered by the sluggish kinetics of the oxygen reduction reaction (ORR), which traditionally necessitates the use of high-cost platinum group metal catalysts. The indispensability of these metal catalysts stems from their ability to overcome kinetic barriers, but their high cost and scarcity necessitate alternative strategies. In this context, porous organic polymers (POPs), which are built up from the molecular level, are emerging as promising precursors to produce carbonaceous catalysts owning to their cost-effectiveness, high electrical conductivity, abundant active sites and extensive surface area accessibility. To enhance the intrinsic ORR activity and optimize the performance of these electrocatalysts, recognizing, designing, and increasing the density of active sites are identified as three crucial steps. These steps, which form the core of our review, serve to elucidate the link between the material structure design and ORR performance evaluation, thereby providing valuable insights for ongoing research in the field. Leveraging the precision of polymer skeletons based on molecular units, POP-derived carbonaceous catalysts provide an excellent platform for in-depth exploration of the role and working mechanism for the specific active site during the ORR process. In this review, the recent advances pertaining to the synthesis techniques and electrochemical functions of various types of active sites, pinpointed from POPs, are systematically summarized, including heteroatoms, surficial substituents and edge/defects. Notably, the structure–property relationship, between these active sites and ORR performance, are discussed and emphasized, which creates guidelines to shed light on the design of high-performance ORR electrocatalysts. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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17 pages, 2497 KiB

Open AccessFeature PaperReview

A Review on Cyanide Gas Elimination Methods and Materials

by Xuanlin Yang, Liang Lan, Ziwang Zhao, Shuyuan Zhou, Kai Kang, Hua Song and Shupei Bai

Molecules 2022, 27(20), 7125; https://doi.org/10.3390/molecules27207125 - 21 Oct 2022

Cited by 7 | Viewed by 2185

Abstract

Cyanide gas is highly toxic and volatile and is among the most typical toxic and harmful pollutants to human health and the environment found in industrial waste gas. In the military context, cyanide gas has been used as a systemic toxic agent. In [...] Read more.

Cyanide gas is highly toxic and volatile and is among the most typical toxic and harmful pollutants to human health and the environment found in industrial waste gas. In the military context, cyanide gas has been used as a systemic toxic agent. In this paper, we review cyanide gas elimination methods, focusing on adsorption and catalysis approaches. The research progress on materials capable of affecting cyanide gas adsorption and catalytic degradation is discussed in depth, and the advantages and disadvantages of various materials are summarized. Finally, suggestions are provided for future research directions with respect to cyanide gas elimination materials. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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45 pages, 11031 KiB

Open AccessReview

Covalent Organic Frameworks for Chemical and Biological Sensing

by Shiji Zhang, Danqing Liu and Guangtong Wang

Molecules 2022, 27(8), 2586; https://doi.org/10.3390/molecules27082586 - 18 Apr 2022

Cited by 24 | Viewed by 4774

Abstract

Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers with polygonal porosity and highly ordered structures. The most prominent feature of the COFs is their excellent crystallinity and highly ordered modifiable one-dimensional pores. Since the first report of them in [...] Read more.

Covalent organic frameworks (COFs) are a class of crystalline porous organic polymers with polygonal porosity and highly ordered structures. The most prominent feature of the COFs is their excellent crystallinity and highly ordered modifiable one-dimensional pores. Since the first report of them in 2005, COFs with various structures were successfully synthesized and their applications in a wide range of fields including gas storage, pollution removal, catalysis, and optoelectronics explored. In the meantime, COFs also exhibited good performance in chemical and biological sensing, because their highly ordered modifiable pores allowed the selective adsorption of the analytes, and the interaction between the analytes and the COFs’ skeletons may lead to a detectable change in the optical or electrical properties of the COFs. In this review, we firstly demonstrate the basic principles of COFs-based chemical and biological sensing, then briefly summarize the applications of COFs in sensing some substances of practical value, including some gases, ions, organic compounds, and biomolecules. Finally, we discuss the trends and the challenges of COFs-based chemical and biological sensing. Full article

(This article belongs to the Special Issue Potential Applications of Functional Porous Organic Frameworks)

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Potential Applications of Functional Porous Organic Frameworks

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